The first alpha version of PHP 8.0.0 is now available for testing.

PHP 8.0.0 Alpha 1

 Core:
  . Removed the pdo_odbc.db2_instance_name php.ini directive. (Kalle)
  . Fixed bug #77619 (Wrong reflection on MultipleIterator::__construct).
    (Fabien Villepinte)
  . Fixed bug #65274 (Enhance undefined class constant error with class name).
    (Nikita)
  . Fixed bug #49555 (Fatal error "Function must be a string" message should be
    renamed). (Nikita)
  . Fixed bug #70839 (Converting optional argument to variadic forbidden by LSP
    checks). (Nikita)
  . Fixed bug #69084 (Unclear error message when not implementing a renamed
    abstract trait function). (Nikita)
  . Fixed bug #62609 (Allow implementing Traversable on abstract classes).
    (Nikita)
  . Fixed bug #79462 (method_exists and property_exists incoherent behavior).
    (cmb)
  . Fixed bug #79368 ("Unexpected end of file" is not an acceptable error
    message). (Alex Dowad)
  . Fixed bug #36365 (scandir duplicates file name at every 65535th file).
    (cmb)
  . Use SSE2 instructions do locale independent strtolower. (Laruence)
  . Fixed bug #79521 (Check __set_state structure). (carusogabriel)
  . Fixed bug #79467 (data:// wrappers are writable). (cmb)
  . Implemented FR #47074 (phpinfo() reports "On" as 1 for the some
    extensions). (cmb)
  . Implemented FR #72089 (require() throws fatal error instead of exception).
    (Nikita)
  . Fixed bug #77966 (Cannot alias a method named "namespace"). (Nikita)

- BZ2:
  . Fixed bug #71263 (fread() does not report bzip2.decompress errors). (cmb)

- CURL:
  . Bumped required libcurl version to 7.29.0. (cmb)

- Date:
  . Fixed bug #65547 (Default value for sunrise/sunset zenith still wrong).
    (cmb)
  . Fixed bug #69044 (discrepancy between time and microtime). (krakjoe)

- DOM:
  . Add property DOMXPath::$registerNodeNamespaces and constructor argument
    that allow global flag to configure query() or evaluate() calls.

- Enchant:
  . Add LIBENCHANT_VERSION macro
  . Deprecate enchant_broker_set_dict_path, enchant_broker_get_dict_path
    enchant_dict_add_to_personal and enchant_dict_is_in_session
  . Add enchant_dict_add and enchant_dict_is_added functions
  . Use libenchant-2 when available

- FPM:
  . Fixed bug #64865 (Search for .user.ini files from script dir up to
    CONTEXT_DOCUMENT_ROOT). (Will Bender)

- GD:
  . Fixed bug #55005 (imagepolygon num_points requirement). (cmb)
  . Replaced gd resources with objects. (Mark Randall)
  . Made the $num_points parameter of php_imagepolygon optional. (cmb)
  . Removed deprecated image2wbmp(). (cmb)
  . Removed deprecated png2wbmp() and jpeg2wbmp(). (cmb)
  . Added imagegetinterpolation(). (cmb)

- Iconv:
  . Dropped support for iconv without proper errno setting. (cmb)

- Intl:
  . Removed deprecated INTL_IDNA_VARIANT_2003. (cmb)

- JIT:
  . Fixed bug #79582 (Crash seen when opcache.jit=1235 and
    opcache.jit_debug=2). (Laruence)
  . Fixed bug #77857 (Wrong result if executed with JIT). (Laruence)
  . Fixed bug #79255 (PHP cannot be compiled with enable JIT).
    (Laruence, Dmitry)

- JSON:
  . The JSON extension is now an integral part of PHP and cannot be disabled
    as per RFC:   https://wiki.php.net/rfc/always_enable_json (tandre)

- LDAP:
  . Removed deprecated ldap_sort. (mcmic)

- MBString:
  . Fixed bug #76999 (mb_regex_set_options() return current options). (cmb)
  . Removed the unused $is_hex parameter from mb_decode_numericentity(). (cmb)

- MySQLi:
  . Fixed bug #76809 (SSL settings aren't respected when persistent connections
    are used). (fabiomsouto)

- mysqlnd:
  . Fixed #60594 (mysqlnd exposes 160 lines of stats in phpinfo). (PeeHaa)

- OpCache:
  . Fixed bug #78654 (Incorrectly computed opcache checksum on files with
    non-ascii characters). (mhagstrand)
  . Fixed bug #76535 (Opcache does not replay compile-time warnings). (Nikita)
  . Fixed bug #79665 (ini_get() and opcache_get_configuration() inconsistency).
    (cmb)

- OpenSSL:
  . Added Cryptographic Message Syntax (CMS) support. (Eliot Lear)

- PCRE:
  . Don't ignore invalid escape sequences. (sjon)

- PGSQL:
  . Bumped required libpq version to 9.1. (cmb)

- PDO:
  . Changed default PDO error mode to exceptions. (AllenJB)
  . Fixed bug #77849 (Disable cloning of PDO handle/connection objects).
    (camporter)

- PDO_OCI:
  . Added support for setting and getting the oracle OCI 18c call timeout.
    (camporter)

- PDO_PGSQL:
  . Bumped required libpq version to 9.1. (cmb)

- phpdbg:
  . Fixed bug #76596 (phpdbg support for display_errors=stderr). (kabel)
  . Fixed bug #76801 (too many open files). (alekitto)
  . Fixed bug #77800 (phpdbg segfaults on listing some conditional breakpoints).
    (krakjoe)
  . Fixed bug #77805 (phpdbg build fails when readline is shared). (krakjoe)

- Reflection:
  . Fixed bug #78697 (ReflectionClass::implementsInterface - inaccurate error
    message with traits). (villfa)
  . Implement ReflectionProperty::hasDefaultValue and
    Reflection::getDefaultValue (beberlei)
  . Fixed bug #64592 (ReflectionClass::getMethods() returns methods out of
    scope). (Nikita)
  . Fixed bug #77325 (ReflectionClassConstant::$class returns wrong class when
    extending). (Nikita)
  . Fixed bug #69180 (Reflection does not honor trait conflict resolution /
    method aliasing). (Nikita)
  . Fixed bug #74939 (Nested traits' aliased methods are lowercased). (Nikita)
  . Implement #79628 (Add $filter parameter for ReflectionClass::getConstants
    and ReflectionClass::getReflectionConstants) (carusogabriel)

- Session:
  . Fixed bug #78624 (session_gc return value for user defined session
    handlers). (bshaffer)
  . Fixed bug #73529 (session_decode() silently fails on wrong input). (cmb)

- SimpleXML:
  . Fixed bug #75245 (Don't set content of elements with only whitespaces).
    (eriklundin)
  . Fixed bug #63575 (Root elements are not properly cloned). (cmb)

- sodium:
  . Fixed bug #77646 (sign_detached() strings not terminated). (Frank)

- SQLite3:
  . Added SQLite3::setAuthorizer() and respective class constants. (bohwaz)

- SPL:
  . Fixed bug #71236 (Second call of spl_autoload_register() does nothing if it
    has no arguments). (Nikita)
  . Fixed bug #65006 (spl_autoload_register fails with multiple callables using
    self, same method). (Nikita)

- Standard:
  . Implemented FR #78638 (__PHP_Incomplete_Class should be final). (Laruence)
  . Fixed bug #77204 (getimagesize(): Read error! should mention file path).
    (peter279k)
  . Fixed bug #76859 (stream_get_line skips data if used with data-generating
    filter). (kkopachev)
  . Fixed bug #78385 (parse_url() does not include 'query' when question mark
    is the last char). (Islam Israfilov)
  . Fixed bug #75902 (str_replace should warn when misused with nested arrays).
    (Nikita)
  . Fixed bug #47983 (mixed LF and CRLF line endings in mail()). (cmb)
  . Made quoting of cmd execution functions consistent. (cmb)

- tidy:
  . Removed the unused $use_include_path parameter from tidy_repair_string().
    (cmb)

- XML:
  . Fixed bug #76874 (xml_parser_free() should never leak memory). (Nikita)

- XMLWriter:
  . Changed functions to accept/return XMLWriter objects instead of resources.
    (cmb)
  . Implemented FR #79344 (xmlwriter_write_attribute_ns: $prefix should be
    nullable). (cmb)

- Zip:
  . Fixed bug #72374 (remove_path strips first char of filename). (tyage, Remi)
  . Add ZipArchive::setMtimeName and ZipArchive::setMtimeIndex methods. (Remi)
  . Add ZipArchive::setProgressCallback method (since libzip 1.3.0). (Remi)
  . Add ZipArchive::setCancelCallback method (since libzip 1.6.0). (Remi)
  . Add optional "flags" parameter to ZipArchive::addEmptyDir, addFile and
    addFromString methods. (Remi)
  . Add "flags" options to ZipArchive::addGlob and addPattern methods
    keeping previous behavior having FL_OVERWRITE by default. (Remi)
  . Add ZipArchive::replaceFile() method. (Remi)
  . Add lastId property to ZipArchive. (Remi)
  . ZipArchive::status and ZipArchive::statusSys properties and
    ZipArchive::getStatusString() method stay valid after the archive
    is closed. (Remi)
  . Fixed bug #50678 (files extracted by ZipArchive class lost their
    original modified time). (Remi)
  . Implemented FR #77960 (add compression / encryption options for
    ZipArchive::addGlob and ZipArchive::addPattern). (Remi)
  . Add ZipArchive::EM_UNKNOWN and ZipArchive::EM_TRAD_PKWARE constants. (Remi)
  . Add ZipArchive::isCompressionMethodSupported() and
    ZipArchive::isEncryptionMethodSupported() method (libzip 1.7.0). (Remi)

- Zlib:
. Fixed bug #71417 (fread() does not report zlib.inflate errors). (cmb)